In a long term evolution (Long Term Evolution, LTE) system, in an intra-evolved UMTS terrestrial radio access network (intra-Evolved UMTS Terrestrial Radio Access Network, intra-E-UTRAN), and based on different handover reference points, two handover types may exist, including X2-based handover (X2 handover) and S1-based handover (S1 handover).
In X2 handover, an X2 interface between a source base station (eNB) and a target eNB acts as a reference point, and during a handover procedure, a mobility management entity (Mobility Management Entity, MME) to which a user equipment (User Equipment, UE) is attached does not change. That is, the X2 handover is based on a premise that an S1 interface exists between the source eNB and the MME to which the UE is attached, and an S1 interface exists between the MME to which the UE is attached and the target eNB. In S1 handover, an S1 interface acts as a reference point, and in this case, the MME to which the UE is attached may change, and a source MME decides whether it is required to change the MME to which the UE is attached and to select a new MME.
After a relay node (Relay Node, RN) is introduced into the LTE system, for handover of a UE in coverage of the RN, the RN cannot correctly decide a handover type.